**Spotlight: Sharp EL-5200**

As
we come on the 13^{th}
(April 16) anniversary of this blog, I want to thank you. Blogging
about mathematics and calculators is a joy in my life and I’m
grateful for your support.

Today’s spotlight is about an early graphing calculator, which is a rare collector’s item today: the Sharp EL-5200, also known as the Sharp EL-9000.

**Quick Facts**

Model: EL-5200/EL-9000

Company: Sharp

Timeline: 1986 – late 1980s

Type: Graphing, Programmable

Memory: 5,120 bytes

Power: 2 x CR2032 batteries

**Keyboard**

There are excellent reviews and articles on the Sharp EL-5200/EL-9000, please check out the Sources section below.

The EL-5200 is a folding calculator which is housed in a wallet. On the left side, we have the scientific keys, the arrow keys, memory keys, and the numeric keypad. The keys are the normal calculator keys.

On the right side, there are the alphabetic keys and the utility keys. I think the key style on the right side is a membrane keyboard, but I am not sure.

**The
Four Main Modes**

The four main modes of the Sharp EL-5200 are, which are listed in switch order:

STAT mode

COMP mode

AER II mode

AER I mode

AER II and AER I modes are programming mode, which is called the Algebraic Expression Reserve mode. The AER I mode is the classic AER mode while AER II is the newer version of programming mode.

The manual to the EL-9000 can be downloaded here: http://basic.hopto.org/basic/manual/Sharp%20EL-9000%20EN.pdf

__STAT
Mode__

This is the calculator's statistics mode. Upon switching to this mode, we have the option of storing data points. Data points are stored in array S while basic statistics are stored in array Z. The basic statistics stored in array Z are:

Z[1] = n

Z[2] = Σx

Z[3] = Σx^2

Z[4] = Σxy

Z[5] = Σy

Z[6] = Σy^2

Be aware when you decide to store data, it takes up programming memory.

Three keys are remapped as follows:

[ RM ]: CD. Clear data. Erases a data point.

[ ⇒M ] (x, y): Adds a comma between the x point and y point.

[ M+ ] DATA: Adds a data point.

The statistic variables are access through the second function ([2ndF]) of the numeric keypad and arithmetic keys.

Linear regression is offered in the form of y = a + bx. The variable a is the y-intercept while the variable b is the slope.

Adding × n before pressing [ M+ ] {DATA} adds the frequency to the data point.

Graphs of statistical data are available, including histograms, linear regression lines, and scatter plots.

Fairly simple.

__COMP
MODE__

This is our calculation mode. In addition to our regular scientific calculator, which operates in algebraic mode, there are other sub-modes included in COMP Mode.

__Graphing__

We can graph up to two functions at one time. The [ RANGE ] key allows to set the range parameters, while the [ AUTO ] key sets the zoom level automatically. The [DRAW] key draws the graph.

For example, to draw y(x) = x^2 + 5 using automatic zoom, key in [ GRAPH ] [ X ] [ x^2 ] [ + ] 5 [ AUTO ] [ DRAW ].

The screen takes up the entire left hand of the screen. The screen shows one coordinate at a time, X or Y. Switch between the two with the key sequence [ 2ndF ] [ ↑ ] {X<>Y}.

__Matrices__

The EL-5200 can store up to 26 matrices A-Z. Operations include determinant, inverse, transpose, and matrix arithmetic. We can get to the arrays at any time by pressing [ 2ndF] [↓].

In fact, the [ 2ndF ] [ ↓ ] toggles between the text (calculator), graphics, and data/array screen.

The [ 2ndF ] [ A ] {DIM} sequence can set the dimensions of a matrix.

In the data screen, we see two elements at one time.

__Base
Conversions__

Integers can be converted between four bases: hexadecimal, binary, decimal, and octal. (bases 16, 2, 10, and 8, respectively) Not much more than arithmetic is offered.

__Running
Programs__

Finally, COMP mode is where we run AER programs. Scroll through the programs with the [ PRO ] button. Start programs and enter data at the prompts by using the [ COMP ] key.

__AER I MODE__

AER I mode is the classic programming mode for Sharp programming calculators. This mode is meant for simple calculations. The [ f()=/? ] key puts the input form f( )=. Enter the variables in between the parenthesis, and the variables will automatically be prompted. For example f(AB)= prompts for the variable A, then B. Only global variables (A – Z) are used. Implied multiplication is allowed. This mode is similar to the AER mode of EL-5100 from 1979.

Example: Circular Radius and Circumference

Title:

CIR.1

Code:

M: f( R ) = π × R^2 ⇒ A, 2 × π × R ⇒ C

(spaces are added for readability)

__AER
II MODE__

AER II is the full programming mode. In this mode, we can use both global and local variables, with local variables being the default. Local variables include lower case letters and subscript numbers. Subscript numbers are entered by the sequence [ 2ndF ] [ number key ]. In this mode, the [ f()=/? ] key adds a question mark to the variable and creates a prompt. Unlike AER I, implied multiplication is not allowed.

Example: Graphing a Sine Wave

Title:

Graph A×sin(Bx+C). Set radians mode.

Code:

M: A = ? B = ? C = ? GRAPH A × SIN (B × X + C) AUTO DRAW

(spaces are added for readability)

There is no Radians mode command, so the user has to set Radians mode during program execution.

__Common
to Both Program Modes__

M: This is the main loop.

, (comma): Displays the result of a calculation and pauses the execution. Press [ COMP ] to continue.

␣ (open space) : Finishes a calculation without stopping.

◣ (right triangle): Ends the current program or subroutine.

↳ ↰ : Loop markers

(comparison) -Y→[(do if true)] -N→[(do if false)]: If Then Else Structure.

[ 2ndF ] {SUB}: Creates a new subroutine. Switch between subroutines and the main loop by pressing [ 2ndF ] [ ↑ ] or [ 2ndF ] [ ↓ ].

To create a new program, go to either AER I or AER II mode, press [ COMP ], enter the title. The title is not limited to eight characters. Since we do not have string or string functions, include descriptive information and reminders in the title (see the example in AEI II Mode above).

I find the symbols taking a bit getting used to because we have symbols instead of the regular If-Then-Else-End structure, For-Next loop, Lbl-Goto structure, etc. AER can store complex formulas and best are for simple number crunching.

**Overall
Thoughts**

I like the separate alphabetic keys, but the membrane keyboard calls for extra care when using those keys. The number of features of the EL-5200 are very invented and advanced for 1986. I wish the AER programs had line returns instead everything smashed together in wrap around lines, but it is more for readability. The calculator has a nice, compact form and is fun to work with.

In
the future I will be posting AER programs for the EL-5200. It’s
rarity makes the EL-5200/EL-9000 collectible.

**Sources**

Calculator Culture. “Sharp EL-9000 Graphing Calculator from 1986” November 27, 2023.

https://www.youtube.com/watch?v=cw7Gp2Qrmtk

Gelhaus, Matthew & Taia Gelahus. “Sharp EL-5200” gelahus.net. Last Updated December 21, 2023. http://www.gelhaus.net/cgi-bin/page.py?loc:8bit/+content:EL-5200.html Retrieved March 1, 2024.

Magyarra,
Váltás “History and Programming of AER Calculators”.
Milestone in the History of Calculators. Virtual Museum of
Calculators. 2016. Retrieved March 25, 2024.
__http://www.arithmomuseum.com/szamologep.php?id=25&lang=en__

Sharp
Corporation. __Sharp Scientific
Calculator Super Scientific Model EL-9000 Operation Manual__.
1986
http://basic.hopto.org/basic/manual/Sharp%20EL-9000%20EN.pdf

(website hosted by hopto.org) (this the same manual for the EL-5200)

Eddie

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